Republicans, looking to frame Sen. Barack Obama as a candidate outside the mainstream, recently settled on a new tack: deriding him as an out of touch and corrupt urbanite.

At the GOP convention last month, Rudy Giuliani -- the former mayor of quite a large city -- chided the Democratic nominee for minimizing Sarah Palin's experience as mayor of tiny Wasilla, Alaska: "I'm sorry that Barack Obama feels that her home town isn't cosmopolitan enough." The rest of Sen. John McCain's campaign hammered Obama as a product of the "Chicago political machine." And two weeks ago, Palin hailed "pro-America" small towns at a stop in North Carolina.

Many Obama partisans detected a vague racial appeal in the anti-urban framing. But the attacks also highlighted an overlooked aspect of the Illinois senator's rise: that in a country forever in thrall to its frontier and small-town heritage, he is the rare White House contender who really is a creature of the big city.

This raises two questions: Is Obama's ascent a further sign -- on top of volatile gas prices, plummeting home values in the exurbs and recent population upticks even in Baltimore and Newark -- that our cities are back and that the country is making peace with its non-agrarian side? And would a big-city president address as never before the problems of our urban cores -- blighted housing, shoddy public transit, dismal schools?

Obama partisans answer both questions in the affirmative -- with a key qualifier. The Democratic nominee, they say, should be viewed less as the first urban candidate in a long time than as the first metropolitan candidate -- a semantic distinction suggesting that the urban resurgence has a ways to go.

The United States long ago became an urban-suburban nation, with two-thirds of the population now residing in its 100 largest metropolitan areas. Yet recent presidents have reflected the national mythology that we are all Jeffersonian yeoman farmers -- the Democrats hailed from Plains, Ga., and Hope, Ark., and the Republicans were happiest on the ranch.

To find a nominee with as strong a city pedigree as Obama's, you have to go back to New York Gov. Al Smith, the Democratic candidate in 1928, or even further, to Grover Cleveland, who had been mayor of Buffalo. (Michael Dukakis was from genteel Brookline, not Boston proper; John Kerry was more Nantucket than Beacon Hill; and John F. Kennedy was defined by Hyannis Port. Franklin D. Roosevelt's urbanity was bred in the Hudson Valley, while Thomas Dewey lived in Manhattan but fled to his upstate farm on weekends.)

By contrast, Obama grew up in Honolulu and Jakarta and has spent his entire adult life in big cities -- college in Los Angeles and New York, law school in Boston (okay, Cambridge) and 20 years in Chicago, the iconic American city, on which Obama settled as his home and launching pad. As a community organizer, he helped public housing residents take on City Hall; he married a native Chicagoan; and his campaign is based in a Michigan Avenue tower.

His style is as urbane as American politics get -- blazers with no tie, the slow stride across the stage. His political base is even more urban than is typical for a Democrat, while he struggles with rural voters despite playing up his mother's Kansas roots. One of the first interest groups he met with after securing the Democratic nomination in June was an alliance of bicycling advocates. Yet Obama has hardly adopted the sort of agenda we've come to expect from urban candidates -- much to the consternation of some of his supporters. With his organizer background, he could have cast himself as a knight riding to the rescue of cities neglected by Republican administrations. Instead, he has adopted the framing increasingly favored by many mayors and urban-policy types -- promoting America's cities based on their strengths, not their failings. Cities, he argues, are now melded to their suburbs, and, taken as a whole, America's metro areas are the "backbone of regional growth," as he put it in a June speech to the U.S. Conference of Mayors. "Washington remains trapped in an earlier era," he said, "wedded to an outdated 'urban' agenda that focuses exclusively on the problems in our cities, and ignores our growing metro areas, an agenda that confuses anti-poverty policy with a metropolitan strategy, and ends up hurting both."

Obama's emphasis on the metro instead of the city is based in reality: The old lines are blurring as employment patterns have scattered across regions, poverty is growing faster in many suburbs than it is downtown, and more immigrants are settling in the 'burbs. A recent report by the Brookings Institution found that the top 100 metro areas generate three-quarters of the country's economic output while covering 12 percent of its land area.

"If someone from Chicago had run in 1975, it would mean something very different than it does today," said Brookings's Bruce Katz. "Then there really was a strong contrast between cities and suburbs, and that has changed in 30 years."

But casting Obama's urban agenda in metropolitan terms also has political benefits. Although the country has re-embraced the city, its political battleground remains the suburbs, said Robert Lang, a demographer at Virginia Tech's Metropolitan Institute. If elected, he says, Obama should find ways to address urban problems in a suburban context -- focusing not just on West Baltimore or North Philadelphia, say, but also on suburban North Las Vegas, which has more concentrated poverty than Las Vegas proper. The same goes for spending on public transit. "If he frames something like that as being about metro competitiveness, he can do a lot," Lang said. "It should be, 'Hey, suburban guy sitting in traffic, would you like transit?' instead of 'I'm going to take your money and spend it in places you don't visit.'"

This approach fits with Chicago, which has become the epitome of the new metropolis, with its high-rise housing projects replaced by mixed-income town houses and its economy dominated by commodities trading, aerospace and higher education instead of stockyards and steel mills -- "a brainy city, not a brawny city," says Lang. Obama was elected in 1996 to represent a South Side district with many poor residents, but after losing his 2000 run for Congress, he decided to expand his base beyond the urban working class. He engineered the redrawing of his district to encompass the city's Gold Coast, putting him in touch with a Chicago elite that would power his U.S. Senate bid.

Casting city issues as "metro" ones rankles some advocates of the urban poor, who see it as a way to gloss over the despair that remains very much an inner-city phenomenon in many metro areas. The Rev. Jesse Jackson acerbically suggested that Obama was playing down urban poverty to appeal to whites. Obama's typical stump speech generally tucks issues such as urban education woes into his broader policy pitch.

But the politicians who deal most with urban troubles, the nation's mayors, say that the metropolitan framing is a shrewd way to convince better-off urban and suburban dwellers that the core affects the vitality of the whole. "When you think of urban, you think of poor, you think of drugs, you think of crime," said Jerry Abramson, the Democratic mayor of Louisville. "When you think of 'metro,' you realize we are linked together, and that the success of one will have great effect on the success of the other."

Embedded in the nation's founding, America's anti-urban bias culminated after World War II, when the automobile propelled city workers to their own suburban arcadia. As cities declined in the 1960s and '70s, Democratic and Republican presidents alike tried to stanch the bleeding with urban renewal projects and social programs that, even before President Ronald Reagan's cutbacks, fell short of their aims. But the trend turned in the 1990s, as the crime wave ebbed and a new generation, beckoned in part by television programs such as "Friends" and "Seinfeld," tired of the suburbs. The rise of a big-city pol like Obama, said Seattle mayor Greg Nickels (D), "represents something that's been happening below the radar screen for a long time."

Obama hasn't entirely abandoned older conceptions of urban uplift. His platform includes Democratic standbys such as restoring funding to the Community Development Block Grant program, which Republicans deride as a money pit; expanding the earned-income tax credit; investing in job training; creating an affordable-housing trust fund; paying for more cops on the street. He talks of creating 20 "promise neighborhoods" modeled on the Harlem Children's Zone, where an intensive application of services -- from prenatal care on up -- aims to lift an entire neighborhood.

Cincinnati Mayor Mark Mallory, a Democrat, says that he also has hopes for Obama's ability to help cities via the bully pulpit, with rhetoric urging parental responsibility, particularly among African Americans. "To the extent that you can motivate people to change their behaviors, you can change outcomes within cities," said Mallory. But dominating Obama's platform are ideas geared more toward the metropolis as a whole: a big investment in infrastructure, including mass transit and inter-city rail, that he now also bills as a jobs measure; a network of public-private business incubators; new green-technology industries; a White House office of urban policy that will goad governments within metro areas into working together.

Mayors like this package partly because, aside from infrastructure spending, it doesn't cost much in a time of low budgets. Cities need a president who understands that they "are no longer the basket case they are often described as from Washington," said Minneapolis Mayor R.T. Rybak (D). "The skills we need in a president aren't the old skills of putting together a benevolent program for communities that will always be disempowered. We need someone who's done what Obama has done, to go into communities that have been hard hit and understand their assets, mobilize people to help them solve their problems."

But can the first metro president banish all of the negative associations of cities -- as un-American, perilous and snobbish -- that McCain and Palin have invoked? Lang, of Virginia Tech, is doubtful. He suspects that the limits of the urban ascendance would become clear after Obama entered the White House. Soon enough, he predicts, a President Obama may be shopping for a vacation home far from the South Side.

"I'm going to look for him to buy some hillside in Virginia," Lang said. "I wonder if he almost has to do that."